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All living thing are made of cells. The cell is the smallest unit of a living thing. Some organisms are made of a single cell.
These organisms are unicellular and usually too small for you to see directly. Pond water is full of tiny unicellular organisms.
Most of the organisms you see, such as a frog or a water lily, are made up of many cells. Organisms made up of many cells
are called multicellular organisms.
Every living thing is made up of one or more cells. (A polar bear is a multicellular organism) Cells carry out the functions
needed to support life. (Fat cells are animal cells that provide energy as well as insulation). Cells come only from other
living cells. (Each polar bear cub began as a single cell). Scientists seprate cells into two broad categories based on one
key difference: the location of the genetic material cells need to reproduce and function. In a Eukaryotic Cell the genetic
material is in a structure called the nucleus, a structure enclosed by its own membrane.In the Prokaryotic Cell there is no
seprate compartment for the genetic material. Instead, it is in the cytoplasm. Most unicellular organisms are prokaryotic
cells.
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